1. Technical Field
The present invention relates to an apparatus and method for improving the dimensional quality of direct expanded food products. More specifically, the present invention relates to an apparatus and method for improving the dimensional quality of direct expanded food products having complex shapes.
2. Description of the Related Art
The use of extrusion devices in the preparation of direct expanded food products is long practiced. Utilized to produce a variety of products such as ready-to-eat (R-T-E) cereals, snack foods and confections, extrusion remains prominent among food processes because of its versatility and efficiency.
Food processes utilizing extrusion devices typically include an edible substance such as dough which is introduced into a device and conveyed via a screw pump to an inlet where the substance is forced through an extruder die assembly. The extruder die assembly may perform a variety of functions: it may form or shape the extrudate; it may divide the extrudate into a multiple extrudates; it may inject an additive substance into the extrudate; and it may compress and reduce the cross-sectional area of the extrudate. Upon exiting the extruder die assembly, the extruded mass is directly expanded (e.g., via flash puffing) and typically cut into individual pieces using a reciprocating blade mechanism. The resulting individual pieces typically have a uniform, puffed shape with a cross-sectional shape generally corresponding to the outline of the forming die""s exit port. While the characteristics of the resulting individual pieces are satisfactory for simple geometric shapes (e.g., spheres, ovoids, and crescents), the design details of more complex shapes tend to be obscured or eliminated.
For example, FIG. 1a shows the exit face 12 of a forming die 10 used in prior art extruder die assembly. Included within the periphery of the exit face 102 is a complexly shaped exit port 14. The outline 16 of exit port 14 is designed to resemble a hand with four distinct appendages or fingers. When the forming die 10 is utilized in conjunction with a conventional direct expanded food process, the resulting product is a uniformly puffed food piece 18 as shown in FIG. 1b. While the shape of the outline 16 of exit port 14 is somewhat discernable in food piece 18, the design details of the four distinct appendages is generally diminished and obscured. The individual dimensional aspects of the four distinct appendages are simply absorbed by the dimensional aspects of the palm area of the outline 16 of exit port 14.
A need, therefore, exists for an improved apparatus and method for enhancing the quality of dimensional design aspects of extruded, complexly shaped, direct expanded food products.
The present invention overcomes many of the shortcomings inherent in prior art apparatus and methods addressing extruder die assemblies. The present invention comprises an improved extruder die assembly and method for using same to improve the quality of dimensional design aspects of extruded, complexly shaped, direct expanded food products.
The improved system includes an improved extruder die assembly comprising a transition insert section, a plurality of spacer insert elements, an imprinting insert element, and a forming insert element, all of which are coaxially aligned and interlocking. The improved extruder die assembly of the present invention is designed for adaptation to a wide variety of commercial-grade extrusion devices common in the food industry. The imprinting insert element includes at least one prong which, when properly configured, is aligned with a corresponding projection in the forming insert element, and momentarily disrupts the axial flow of an extrudate altering its velocity profile. By disrupting the axial flow the extrudate in close proximity to the projections in the forming insert element prior to its extrusion, the dimensional quality of the resulting direct expanded food piece is greatly improved.
The axial distance between the one or more prongs and its corresponding projection may be adjusted as necessary using spacer insert elements to optimize the dimensional qualities of the resulting food piece depending upon the particular flow characteristics of each extrudate.